July 2, 2011

Electrical Engineering Terms - C

C - Centigrade or Celsius

C-Rate - Battery discharge current in amperes; numerically equal to rated capacity of a cell in ampere-hours.

C2H4 - Ethylene.

C2H6 - Ethane.

Cable - A term generally applied to the larger sizes of bare or weatherproofed (covered) and insulated conductors. It is also applied to describe a number of insulated conductors twisted or grouped together.

Cable Cleaner - A chemical compound used to clean dirt, residual insulation & semi con and other foreign material from an insulated cable during the termination process.

Cable Pulling Lubricant - A chemical compound used to reduce pulling tension by lubricating a cable when pulled into a duct or conduit.

Cable Tray - A rigid structural system used to support cables and raceways. Types of cable trays include ladder, ventilated trough, ventilated channel, and solid bottom

CAIDI - A distribution circuit reliability average interruption duration index. It represents the average time required to restore service to the average customer per sustained interruptions.

CAIFI - The customer average interruption frequency index. It is designed to show trends in customers interrupted and helps to show the number of customers affected out of the whole customer base.

Cal-ISO - See California Independent System Operator.

Calibration - Adjustment of a device so the output is within a specified range for particular values of the input.

California Independent System Operator (Cal-ISO) - The FERC-regulated control area operator of the California transmission grid. Its responsibilities include providing nondiscriminatory access to the grid, managing congestion, maintaining the reliability and security of the grid, and providing billing and

California Power Exchange (CalPX) - Now defunct, this independent California agency was responsible for conducting an auction for the generators seeking to sell energy and for loads that are not otherwise being served by bilateral contracts. The CalPX was responsible for scheduling generati

California Public Utilities Commission (CPUC) - Headquartered in San Francisco, the CPUC regulates telecommunications, electric, natural gas, water, railroad, rail transit and passenger transportation companies. The CPUC is chartered by the State of California to assure consumers have safe, reliable

Calorie - A calorie is the energy required to raise one gram of water one degree Celsius at one atmosphere. The onset of second-degree burns may occur at 1.2 calories per centimeter squared per second. One calorie per centimeter squared per second per second can be

Can - Slang for an overhead transformer.

Candela (cd) - The standard unit for luminous intensity. One candela is equal to one lumen per steradian.

Candlepower - Luminous intensity expressed in candelas.

Candlepower Distribution Curve - A curve, generally polar, representing the variation of luminous intensity of a lamp or luminaire in a plane through the light center.

Capacitance - 1) The ratio of an impressed charge on a conductor to the corresponding change in potential. 2)The ratio of the charge on either conductor of a capacitor to the potential difference between the conductors. 3) The property of being able to collect a char

Capacitor Voltage Transformer - A voltage transformer that uses capacitors to obtain a voltage divider effect. It is utilized at EHV voltages instead of an electromagnetic VT for cost and size purposes.

Capacity (Battery) - The quantity of electricity delivered by a battery under specific conditions, usually expressed in ampere-hours.

Cat 5 Cable - See "Category 5 Cable"

Category 5 Cable - Also known as "Cat 5", this cable is used for fast ethernet and telephone communications. The cable is constructed of 4 twisted pair of copper wire.

Cathode - 1) The negative electrode, that emits electrons or gives off negative ions and toward which positive ions move or collect in a voltaic cell or other such device. 2) The negative pole of a battery.

CB - Circuit Breaker

CDMA - Code Division Multiple Access. CMDA is a technique used mainly with personal communications devices such as mobile phones that digitizes the conversation and tags it with a special frequency code. The data is then scattered across the frequency band. T

Cell (Battery) - An electrochemical device composed of positive and negative plates, separator, and electrolyte which is capable of storing electrical energy.

Cell (Photovoltaic) - See "Photovoltaic Cell".

Cell Voltage (Battery) - See "Nominal Voltage (Battery)".

Cell-Reversal (Battery) - Reversing of polarity within a cell of a multi-cell battery due to over discharge.

CH2H2 - Acetylene

CH4 - Methane.

Characteristic Angle - The angle between the vectors representing two of the energizing quantities applied to a relay used for the declaration of the performance.

Characteristic Curve - A plot or curve displaying the operating values of the characteristic quantities corresponding to various values or combinations of the energizing quantities.

Characteristic Impedance Ratio (C.I.R.) - The maximum value of the system impedance ratio for which the relay performance remains within the prescribed limits of accuracy.

Charge (Battery) - The conversion of electrical energy from an external source, into chemical energy within a cell or battery.

Charge Controller - An electronic device which regulates the voltage applied to a battery or battery bank.

Charge Rate (Battery) - The rate at which current is applied to a secondary cell or battery to restore its capacity.

Charge-Retention (Battery) - The tendency of a charges cell or battery to resist self-discharge.

Check Protection System - An auxiliary protection system intended to prevent tripping due to inadvertent operation of the main protection system.

Cherry Picker - An aerial lift truck. Also see Bucket Truck.

Chlorinated Polyethylene - Chlorinated Polyethylene. CPE, a thermoplastic compound, is used to jacket certain types of power cable.

Choker - A Sling.

Circuit - A conductive path over which an electric charge may flow.

Circuit Breaker - A device that can be used to manually open or close a circuit, and to automatically open a circuit at a predetermined level of over current without damage to itself.

Circuit Insulation Voltage - The highest circuit voltage to earth on which a circuit of a transducer may be used and which determines its voltage test.

Circuit Switchers - Circuit-Switchers are multipurpose switching and protection devices. Often used for switching and protection of transformers, single and back-to-back shunt capacitor banks, reactors, lines, and cables. They can close, carry, and interrupt fault currents.

Circuit Voltage - The greatest root-mean-square (effective) difference of potential between any two conductors of the circuit.

Circular-Mil (cmil) - The area of a circle with a diameter of one mil (1/1000 inch), used to describe the cross-sectional area of a conductor. One cmil equals approximately 0.0000008 square inches.

Class Index - A number which designates an accuracy class.

Clearing Time - The total time needed for a protective device such as a fuse or circuit breaker to clear a fault.

CLF - Refer to "Current Limiting Fuse".

Client - As part of a computer network, where a server is employed, this is the customer or non-server side. When you log onto a server, from another computer, the word "Client" refers to you, your computer or your software.

Climbers - Hooks for climbing poles that are attached to a lineman's boots.

Closing Impulse Time - The time during which a closing impulse is given to the circuit breaker.

Closing Time - Referring to a circuit breaker it is the necessary time for it to close, beginning with the time of energizing of the closing circuit until contact is made in the CB.

CO - Carbon Monoxide.

Coax Cable - See "Coaxial Cable".

Coaxial Cable - Also known as "Coax", this cable is typically used to connect TV to its video source. Coaxial Cable consists of a small copper wire or tube, surrounded by an insulating material and another conductor with a larger diameter, normally copper braid or a cond

Coefficient of Utilization (CU) - The percentage of light generated within a luninaire which ultimately strikes the work surface. It is usually expressed as a decimal percentage.

Coffin Hoist - A chain hoist of any type.

Coil Loss - Power loss in a transformer due to the flow of current. These losses are present only when the transformer is serving a load. Load losses vary by the square of the current magnitude. Load losses are composed of losses due to the current flow.

Cold - Refers to non-energized equipment, lines or circuits.

Collector Roadway (Lighting) - The distributor and collector roadways servicing traffic between major and local roadways. These are roadways used mainly for traffic movements within residential, commercial and industrial areas.

Combination Unilay - A stranding configuration that uses two strand sizes to achieve a 3% reduction in the conductor diameter without compression

Come-a-long - A wire grip for holding a conductor or strand under tension.

Commercial (Lighting) - A business area of a municipality where there are ordinarily many pedestrians during night hours. The definition applies to densely developed business area outside, as well as within, the central part of a municipality. The area contains land use attrac

Compact Stranding - A stranding configuration with concentric strands in which each layer is passed through a compacting die to reduce the conductor diameter by approximately 10%

Competition Transition Charge (CTC) - A charge itemized on customer bills to recover costs associated with investor owned utility investments in generation-related assets and state-mandated contracts with nonutility generators that may now be uneconomic and unrecoverable in the restructured.

Compliance Voltage - The specified maximum voltage that a transducer (or other device) current output must be able to supply while maintaining a specified accuracy.

Compound - An insulating or jacketing material made by mixing two or more ingredients

Compressed - A stranding configuration with concentric strands in which either all layers or the outer layer only is passed through a die to reduce the conductor diameter by 3%

Compression Splice - A compression connector used to join two conductors. There are different designs used for overhead and underground conductors. For overhead conductors, there are different designs for limited and full tension applications.

Concentrator (Photovoltaic) - See "Photovoltaic Centrator".

Concentric Stranding - A stranding configuration in which individual wires are stranded concentrically with no reduction in overall diameter. Typically used for bare conductors

Conduct - The ability of two conductors separated by a dielectric to store electricity when a potential difference exists between the conductors.

Conductivity - The capability of a conductor to carry electricity, usually expressed as a percent of the conductivity of a same sized conductor of soft copper

Conductor - 1) A wire or combination of wires suitable for carrying an electrical current. Conductors may be insulated or bare. 2) Any material that allows electrons to flow through it.

Conductor Loss - See "Coil Loss".

Conductor Shield - A semiconducting material, normally cross-linked polyethylene, applied over the conductor to provide a smooth and compatible interface between the conductor and insulation.

Conduit - A channel for holding and protecting conductors and cables, made of metal or an insulating material, usually circular in cross section like a pipe. Also referred to as Duct.

Conduit Fill - Volumetric measurement of the duct space occupied by the cables inside, expressed as a percent.

Conjunctive Test - A parametric or specific test of a protection system on all components and auxiliary equipment that are connected.

Constant Current Charge - Charging technique where the output current of the charge source is held constant.

Constant Potential Charge - Charging technique where the output voltage of the charge source is held constant and the current is limited only by the resistance of the battery.

Continuity Test - A test performed on a conductor to determine if it is unbroken throughout its length

Continuous - See Continuous Rating.

Continuous Load - An electrical load in which the maximum current is expected to continue for three hours or more

Continuous Rating - The constant voltage or current that a device is capable of sustaining. This is a design parameter of the device.

Conversion Coefficient - The relationship of the value of the measured to the corresponding value of the output.

Coordination - Relating to the protection of the power system, the process of coordinating the fuse, breakers and reclosers of a system so to allow the downstream devices to operate first.

Copolymer - Chains of unlike molecules that are chemically bonded together

Core Balance Current Transformer - A ring-type current transformer in which all primary conductors are passed through the aperture making any secondary current proportional to any imbalance in current.

Core Loss - Power loss in a transformer due to excitation of the magnetic circuit (core). No load losses are present at all times when the transformer has voltage applied.

Corona - See Corona Discharge.

Corona Discharge - An electrical discharge at the surface of a conductor accompanied by the ionization of the surrounding atmosphere. It can be accompanied by light and audible noise.

Coulomb - A unit of electric charge in SI units (International System of Units). A Coulomb is the quantity of electric charge that passes any crossection of a conductor in one second when the current is maintained constant at one ampere.

Counter EMF - Voltage or cell or battery opposing the voltage of the charging source.

Counting Relay - A relay that counts the number of times it is energized and actuates an output after a desired count has been reached.

Cover - Top surface section of the handhole for closing the top access opening of the box section.

CPE - Chlorinated Polyethylene. CPE is a thermoplastic compound that is used to jacket certain types of power cable.

CPUC - See California Public Utilities Commission (CPUC).

Creepage Distance - The shortest distance between two conductors as measured along the device that separates them. Creepage Distance is normally a design parameter of insulators or insulating bushings.

Crest - See Crest Value.

Crest Value - The maximum value of a wave form. This is normally associated with electrical fault magnitude or transients.

Cross-Linked Polyethylene (XLPE) - A Common thermoset insulation material for building wire and cable. It undergoes a cross linking chemical reaction during a curing process that causes the compound molecules to bond, forming heavier molecules.

CSV - Character (or Comma) Separated Values Format, format widely utilized for the exchange of data between different software, in which the data are separated by a known character usually a comma.

CT - See "Current Transformer".

CTC - See Competition Transition Charge.

Cu - The chemical symbol for copper.

CU (Lighting) - Coefficient of Utilization

Current - The movement of electrons in a conductor measured in Amperes.

Current Limiting Fuse - A fuse designed to reduce damaging extremely high current.

Current Transducer - A transducer used for the measurement of A.C. current.

Current Transformer - A transformer used to measure the amount of current flowing in a circuit by sending a lower representative current to a measuring device such as a meter.

Current Transformer Ratio - 1) The ratio of primary amps divided by secondary amps. 2) The current ratio provided by the windings of the CT. For example, a CT that is rated to carry 200 Amps in the primary and 5 Amps in the secondary, would have a CT ratio of 200 to 5 or 40:1.

Cut Off Voltage - Battery Voltage reached at the termination of a discharge. Also Known as the End Point Voltage (EPV).

Cutoff (Lighting) - Luminaire light distribution is classified as cutoff when the candlepower per 1000 lamp lumens does not numerically exceed 25 (2.5%) at an angle of 90 degrees above nadir (horizontal), and 100 (10%) at a vertical angle of 80 degrees above nadir.

Cutoff Angle (Lighting) - With regard to an outdoor lighting luminaire, the angle between the vertical axis and the first line of sight at which the bare light source is not visible.

Cutoff, Full (Lighting) - A luminary light distribution with zero candela at an angle of 90 degrees or above and not more than 10% of emitted light above 80 degrees.

Cutoff, Non (Lighting) - A luminary light distribution where there is no Candela restriction at any angle.

Cutoff, Semi (Lighting) - A luminary light distribution with 5% candela at an angle of 90 degrees or above and not more than 20% of emitted light above 80 degrees.

Cutout - See "Fused Cutout".

Cycle - In Alternating current, the change of the poles from negative to positive and back.

Cycle (Battery) - A sequence of discharge followed by a charge, or a charge followed by a discharge, of a battery under specific conditions.